http://hdl.handle.net/10174/37679 2026-08-03T21:07:18Z http://hdl.handle.net/10174/42038 Title: Site screening requirements for hydrogen geological storage in saline aquifers Authors: Mazezo, Augusto; Pereira, Pedro; Karwan, Khudhur Abstract: Underground hydrogen storage (UHS) in deep saline aquifers is a promising solution for large-scale, long-duration energy storage, vital for addressing renewable intermittency and enabling deep decarbonization. This study presents a benchmarking of requirements and a comprehensive framework for site screening of saline aquifers for hydrogen storage. It integrates technical parameters – such as reservoir quality, seal integrity, and geomechanical stability – with non-technical aspects, including economic viability, regulatory readiness, environmental risk, and social acceptance. Particular focus is given to hydrogen-specific challenges affecting storage integrity, especially geochemical and geomechanical factors. Drawing from experience with natural gas and CO2 storage, the study proposes a multidisciplinary screening workflow to support early-stage project assessment. The findings provide a foundation for future pilot projects, policy development, and regulatory frameworks tailored to UHS in porous media, contributing to the strategic expansion of hydrogen infrastructure and energy system resilience. 2025-12-01T00:00:00Z http://hdl.handle.net/10174/39848 Title: Fluxo de calor em Portugal Continental-Resultados após 40 anos de trabalho. Geothermal Heat Flow in mainland Portugal-Results after 40 years of work Authors: Duque, Maria Rosa Abstract: Abstract: The first measurements of geothermal heat flow density arriving at the Earth’s surface by conduction, in mainland Portugal, began in the early 1980s. After 40 years it is possible to present a set of 36 heat flow density values obtained in boreholes drilled for mining or water prospecting and 16 values from data obtained in wells drilled for oil and gas prospecting in sedimentary basins. Due to the reduced number of measurements in some regions of the country, numerical models were elaborated to obtain 17 heat flow density values that completed the set of data containing a total of 69 heat flow density values. The interpretation of the obtained values is made considering heat sources in the crust,thermal conductivity and temperature gradient values obtained and the location of the measurement sites. The differences obtained between the heat flow values are mainly due to radioactive sources distribution in the crust. An additional source of heat due to exothermic chemical reactions was considered in the Iberian Pyrite Belt. The heat flow from the mantle was considered the same in all the territory studied. Low values of heat flow are associated to Bragança and Morais Massifs. High values of heat flow were obtained in the Iberian Pyrite belt in Alentejo. The heat flow values decrease from the Northern and Central Western parts of the territory to the Southern parts. Resumo: As primeiras medições, em Portugal continental, de fluxo de calor que chega à superfície da Terra por condução, foram feitas no início da década de 80. Atualmente é possível apresentar um conjunto de 69 valores de fluxo de calor obtidos em Portugal continental, por medição direta em furos (36 valores), utilizando dados obtidos durante a realização de furos para prospeção de petróleo ou gás (16 valores), e através de modelos numéricos em algumas regiões sem medições (17 valores). A interpretação dos valores obtidos é feita considerando fontes de calor na crusta, valores de condutividade térmica e de gradientes de temperatura obtidos e localização das medições. As diferenças entre os valores obtidos deve-se principalmente à distribuição de fontes radioativas na crusta. Valores baixos de fluxo de calor aparecem associados aos Maciços de Bragança e de Morais. Na Faixa Piritosa Ibérica, no Alentejo, foram obtidos valores elevados de fluxo de calor. 2025-03-31T23:00:00Z